DOCSLIB.ORG

The Peripheral Nervous System

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Peripheral Nervous System The Peripheral Nervous System Dr. Ali Ebneshahidi Peripheral Nervous System (PNS) – Consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves. – Serves as a critical link between the body and the central nervous system. – peripheral nerves contain an outermost layer of fibrous connective tissue called epineurium which surrounds a thinner layer of fibrous connective tissue called perineurium (surrounds the bundles of nerve or fascicles). Individual nerve fibers within the nerve are surrounded by loose connective tissue called endoneurium. Cranial Nerves Cranial nerves are direct extensions of the brain. Only Nerve I (olfactory) originates from the cerebrum, the remaining 11 pairs originate from the brain stem. Nerve I (Olfactory)- for the sense of smell (sensory). Nerve II (Optic)- for the sense of vision (sensory). Nerve III (Oculomotor)- for controlling muscles and accessory structures of the eyes ( primarily motor). Nerve IV (Trochlear)- for controlling muscles of the eyes (primarily motor). Nerve V (Trigeminal)- for controlling muscles of the eyes, upper and lower jaws and tear glands (mixed). Nerve VI (Abducens)- for controlling muscles that move the eye (primarily motor). Nerve VII (Facial) – for the sense of taste and controlling facial muscles, tear glands and salivary glands (mixed). Nerve VIII (Vestibulocochlear)- for the senses of hearing and equilibrium (sensory). Nerve IX (Glossopharyngeal)- for controlling muscles in the pharynx and to control salivary glands (mixed). Nerve X (Vagus)- for controlling muscles used in speech, swallowing, and the digestive tract, and controls cardiac and smooth muscles (mixed). Nerve XI (Accessory)- for controlling muscles of soft palate, pharynx and larynx (primarily motor). Nerve XII (Hypoglossal) for controlling muscles that move the tongue ( primarily motor). Spinal Nerves • Spinal nerves are mixed nerves where both sensory and motor nerve fibers are found in each nerve, allowing these nerves to have two-way communication between the spinal cord and the arms, legs, neck, and body trunk. • Except in the thoracic region, all spinal nerves form plexuses. In each plexus, nerve fibers of various spinal nerves are sorted and recombined, resulting in different nerve fibers from different spinal nerves reaching the same parts. Plexuses Plexuses- are a network of spinal nerves. 1) Cervical plexus (C1- C4): most branches are cutaneous and supply the skin of face and neck. Other branches supply muscles of the anterior neck. Fibers of C3/ 4/5 Cervical nerves form the right and left phrenic nerve which supply the diaphragm. 2) Brachial plexus (C5 – T1): form brachial plexus. Major branches: main branches emerging from the brachial plexus include the following: a) musculcutaneous nerve: supply muscle of the ant. arm and skin of forearm. b) ulnar nerve: supply muscles of forearm, hands and skin of hands. c) median nerve: supply muscles of the forearm and muscles of hands. d) radial nerve: supply muscles of the post. arm and skin of forearm and hands. It is the largest brnch of C- plexus. e) axillary nerve: supply muscles of the skin of the superior, lateral, and posterior regions of the arm. other nerves associated with brachial plexus are: f) lateral & medial pectoral nerves: supply the pectoralis major and minor muscles. g) dorsal scapular nerve: supply the rhomboideus major and levator scapulae. h) lower subscapularis nerve: supply the subscapularis and teres major muscles. i) thoracic dorsal nerve: supply the latissimus dorsi muscle. j) the suprascapular nerve: supply the supraspinatous and infra- spinatous muscles. 3) lumbosacral plexus (T12 - S5): Major branches : a) obturator nerve: supply the Adductor muscles of the thigh. b) femoral nerve: supply quadriceps muscles. It is the longest nerve of the lumbar plexus. c) sciatic nerve: divides into tibial and common peroneal nerve. It supply muscles and skin in the thighs, legs, and feet. It is the largest and longest nerve in the body. other nerves associated with lumbar plexus are: d) pudendal nerve: supply the muscles of perineum. e) inferior & superior gluteal nerve: supply the gluteal muscles and the tensor fascia lata muscle. Dermatomes Dermatome: is an area of skin that the sensory nerve fibers of a particular spinal nerve innervate. All spinal nerves except C1 has dermatomes (example: the skin of upper limbs is supplied by ventral rami of C5- T1). .
Load more

Recommended publications
  • Radical Transsternal Thymectomy David Park Mason, MD
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Radical Transsternal Thymectomy David Park Mason, MD bnormalities of the thymus comprise more than half of generalized enlargement of the thymic gland caused by dif- Athe lesions found in the anterior mediastinal compart- fuse thymocyte proliferation. Thymic hyperplasia is an im- ment in adults. Greater than 95% of the tumors of the thymus munologic condition.10 In children, thymic hyperplasia can are thymomas that originate from thymic epithelial cells. be associated with a variety of endocrine disorders including They generally present as an incidental radiographic finding. hyperthyroidism. In adults, thymic hyperplasia has been as- They are of surgical importance both as isolated entities as sociated with thymoma as well as many immune dysfunction well as in association with myasthenia gravis (MG). Surgical syndromes—the most notable being myasthenia gravis. Re- excision is the cornerstone of therapy for thymoma.1 In ad- moval of the thymus gland, by a variety of surgical ap- dition, thymectomy is an integral component of the manage- proaches, appears to influence the immune dysfunction ob- ment of myasthenia gravis. served in myasthenia gravis.7 The mechanism of this Ludwig Rehn performed the first thymic operation in 1896, a influence, and the relative benefit of removing all residual or transcervical exothymopexy for a patient with an enlarged thy- ectopic thymic tissue, is unclear. 2 mus causing episodes of suffocation. He pulled the enlarged The most frequent asymptomatic indication for thymec- thymus out of the mediastinum and performed a pexy of the tomy is thymoma.
    [Show full text]
  • Nerve Ultrasound in Dorsal Root Ganglion Disorders: Smaller Nerves Lead to Bigger Insights
    Clinical Neurophysiology 130 (2019) 550–551 Contents lists available at ScienceDirect Clinical Neurophysiology journal homepage: www.elsevier.com/locate/clinph Editorial Nerve ultrasound in dorsal root ganglion disorders: Smaller nerves lead to bigger insights See Article, pages 568–572 After decades of having to make do with electric stimulation representing the fascicles, bundled together in a large outer cable and recording (i.e. nerve conduction studies, electromyography sheath (van Alfen et al., 2018). and evoked potentials), nerve ultrasound now provides the oppor- Next, it is important to realize what the ratio between axon/ tunity to improve neurodiagnostic patient care by deploying a myelin and connective tissue in a given nerve segment is, and powerful tool to detect neuromuscular pathology in an accurate how that ratio changes from the proximal root to the distal end and patient-friendly way (Mah et al., 2018; Walker et al., 2018). branches (Schraut et al., 2016). Connective tissue elements of the Nerve ultrasound is also increasingly providing neurologists and perineurium and epineurium are relatively sparse at the very prox- clinical neurophysiologists with the opportunity to increase their imal root and plexus levels, with an average connective tissue con- insight in the pathophysiology of peripheral nervous system tent of around 25–30%. Ultrasonographically, this means that roots (PNS) pathology. In this issue of Clinical Neurophysiology, Leadbet- will always look rather black in appearance without much dis- ter and coworkers (Leadbetter et al., 2019) describe the results of cernible fascicular architecture, as the sparseness of connective tis- their study on nerve ultrasound for diagnosing sensory neuronopa- sue elements provides relatively few reflectors to create an image thy in spinocerebellar ataxia type 2 and CANVAS syndrome.
    [Show full text]
  • Of the Pediatric Mediastinum
    MRI of the Pediatric Mediastinum Dianna M. E. Bardo, MD Director of Body MR & Co-Director of the 3D Innovation Lab Disclosures Consultant & Speakers Bureau – honoraria Koninklijke Philips Healthcare N V Author – royalties Thieme Publishing Springer Publishing Mediastinum - Anatomy Superior Mediastinum thoracic inlet to thoracic plane thoracic plane to diaphragm Inferior Mediastinum lateral – pleural surface anterior – sternum posterior – vertebral bodies Mediastinum - Anatomy Anterior T4 Mediastinum pericardium to sternum Middle Mediastinum pericardial sac Posterior Mediastinum vertebral bodies to pericardium lateral – pleural surface superior – thoracic inlet inferior - diaphragm Mediastinum – MR Challenges Motion Cardiac ECG – gating/triggering Breathing Respiratory navigation Artifacts Intubation – LMA Surgical / Interventional materials Mediastinum – MR Sequences ECG gated/triggered sequences SSFP – black blood SE – IR – GRE Non- ECG gated/triggered sequences mDIXON (W, F, IP, OP), eTHRIVE, turbo SE, STIR, DWI Respiratory – triggered, radially acquired T2W MultiVane, BLADE, PROPELLER Mediastinum – MR Sequences MRA / MRV REACT – non Gd enhanced Gd enhanced sequences THRIVE, mDIXON, mDIXON XD Mediastinum – Contents Superior Mediastinum PVT Left BATTLE: Phrenic nerve Vagus nerve Structures at the level of the sternal angle Thoracic duct Left recurrent laryngeal nerve (not the right) CLAPTRAP Brachiocephalic veins Cardiac plexus Aortic arch (and its 3 branches) Ligamentum arteriosum Thymus Aortic arch (inner concavity) Trachea Pulmonary
    [Show full text]
  • Student Academic Learning Services Nervous System Quiz
    Student Academic Learning Services Page 1 of 8 Nervous System Quiz 1. The term central nervous system refers to the: A) autonomic and peripheral nervous systems B) brain, spinal cord, and cranial nerves C) brain and cranial nerves D) spinal cord and spinal nerves E) brain and spinal cord 2. The peripheral nervous system consists of: A) spinal nerves only B) the brain only C) cranial nerves only D) the brain and spinal cord E) the spinal and cranial nerves 3. Which of these cells are not a type of neuroglia found in the CNS: A) astrocytes B) microglia C) Schwann cells D) ependymal cells E) oligodendrocytes 4. The Schwann cells form a myelin sheath around the: A) dendrites B) cell body C) nucleus D) axon E) nodes of Ranvier 5. The neuron processes that normally receives incoming stimuli are called: A) axons B) dendrites C) neurolemmas D) Schwann cells E) satellite cells www.durhamcollege.ca/sals Student Services Building (SSB), Room 204 905.721.2000 ext. 2491 This document last updated: 7/29/2011 Student Academic Learning Services Page 2 of 8 6. Collections of nerve cell bodies inside the PNS are called: A) ganglia B) tracts C) nerves D) nuclei E) tracts or ganglia 7. Which of the following best describes the waxy-appearing material called myelin: A) an outermembrane on a neuroglial cell B) a lipid-protein (lipoprotein) cell membrane on the outside of axons C) a mass of white lipid material that surrounds the cell body of a neuron D) a mass of white lipid material that insulates the axon of a neuron E) a mass of white lipid material that surrounds the dendrites of a neuron 8.
    [Show full text]
  • Superficial (And Intermediate) Cervical Plexus Block
    Superficial (and Intermediate) Cervical Plexus Block Indications: -Tympanomastoid surgery. When combined with the auricular branch of the vagus (‘nerve of arnold’) by infiltrating subcutaneously into the medial side of the tragus), obviates the need for opiates. -Pinnaplasty or Otoplasty -Lymph node excision (within the anterior and posterior triangles of the neck) -Clavicular surgery or fractures (may require intermediate cervical plexus block and its combination with interscalene block, see below) -Central Venous Catheters: Renal replacement therapy central venous catheters, tunnelled central venous catheters and portacaths inserted into the subclavian or jugular veins (may require combination with ‘Pecs 1’ block for component of pain below the clavicle) -Tracheostomy (see below discussion on safety profile of performing bilateral blocks and risks of respiratory distress due to phrenic nerve or recurrent largyngeal nerve block) -More commonly in adults: thyroid (again, bilateral) and carotid surgery Contraindications: -local sepsis or rash Anatomy: The cervical plexus arises from C1-C4 mixed spinal nerves (fig. 1): Somatic sensory branches: -arise from C2-C4 as the mixed spinal nerves leave the sulcus between the anterior and posterior tubercles of the transverse process (note C7 does not have an anterior tubercle or bifid spinous process): -pass between longus capitis and middle scalene perforating the prevertebral fascia. Note at C4 level the anterior scalene has largely disappeared having taken the bulk of its vertebral bony origin lower down. The bulkiest of the scalene muscles is the middle scalene and remains in view at this level: -then pass behind the internal jugular vein out into the potential space between the investing layer of deep fascia ensheathing the sternocleidomastoid, and the prevertebral layer of deep fascia covering levator scapulae (fig.
    [Show full text]
  • 33. Spinal Nerves. Cervical Plexus
    GUIDELINES Students’ independent work during preparation to practical lesson Academic discipline HUMAN ANATOMY Topic SPINAL NERVES. CERVICAL PLEXUS. 1. Relevance of the topic: The knowledge of structures of the peripheral nervous system, particularly cervical plexus and its branches is the base of clinical thinking in terms of differential diagnosis for the doctor of any specialty, but above all a neurologist, vertebroneurologist, traumatologist, dermatologist, general practitioner. 2. Specific objectives of practical lesson - Analyse the composition of fibres of anterior and posterior roots of spinal nerves. - Explain the formation of spinal nerve. - Suggest the definition of spinal nerve. - Classify spinal nerve branches. - Explain functional anatomy of thoracic spinal nerve branches. - Define term "plexus of somatic nerves" including the formation of cervical plexus. - Draw a scheme of spinal nerve: o а - in cervical region of spinal cord (except for the CVIII); o b - in thoracic region of spinal cord; o c - on the level of SII – SIV. - Analyse the connection of somatic nerve (thoracic spinal nerve) with ganglia of sympathetic trunk. - Create the conception of grey and white connecting branches in the functional aspect. 3. Basic level of preparation (interdisciplinary integration) of the student includes knowledge of medical biology and histology of the development of nervous system in phylogenesis and ontogenesis. Name of previous disciplines Obtained skills 1. Medical Biology and Histology Know ontogenesis and phylogenesis of nervous system. The structure of the neuron. 2. Sections of Human Anatomy: - osteology The student should have skills to describe the structure of - myology the spine in general, to be able to demonstrate structural features of the cervical vertebrae, their connections with each other and with the bones of the skull.
    [Show full text]
  • Study Guide Medical Terminology by Thea Liza Batan About the Author
    Study Guide Medical Terminology By Thea Liza Batan About the Author Thea Liza Batan earned a Master of Science in Nursing Administration in 2007 from Xavier University in Cincinnati, Ohio. She has worked as a staff nurse, nurse instructor, and level department head. She currently works as a simulation coordinator and a free- lance writer specializing in nursing and healthcare. All terms mentioned in this text that are known to be trademarks or service marks have been appropriately capitalized. Use of a term in this text shouldn’t be regarded as affecting the validity of any trademark or service mark. Copyright © 2017 by Penn Foster, Inc. All rights reserved. No part of the material protected by this copyright may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the copyright owner. Requests for permission to make copies of any part of the work should be mailed to Copyright Permissions, Penn Foster, 925 Oak Street, Scranton, Pennsylvania 18515. Printed in the United States of America CONTENTS INSTRUCTIONS 1 READING ASSIGNMENTS 3 LESSON 1: THE FUNDAMENTALS OF MEDICAL TERMINOLOGY 5 LESSON 2: DIAGNOSIS, INTERVENTION, AND HUMAN BODY TERMS 28 LESSON 3: MUSCULOSKELETAL, CIRCULATORY, AND RESPIRATORY SYSTEM TERMS 44 LESSON 4: DIGESTIVE, URINARY, AND REPRODUCTIVE SYSTEM TERMS 69 LESSON 5: INTEGUMENTARY, NERVOUS, AND ENDOCRINE S YSTEM TERMS 96 SELF-CHECK ANSWERS 134 © PENN FOSTER, INC. 2017 MEDICAL TERMINOLOGY PAGE III Contents INSTRUCTIONS INTRODUCTION Welcome to your course on medical terminology. You’re taking this course because you’re most likely interested in pursuing a health and science career, which entails ­proficiency­in­communicating­with­healthcare­professionals­such­as­physicians,­nurses,­ or dentists.
    [Show full text]
  • A Brief Introduction Into the Peripheral Nervous System
    A Brief Introduction into the Peripheral Nervous System Bianca Flores, PhD Candidate, Neuroscience Tuesday, October 15th, 2019 Brief overview: • What are you hoping to learn? • Subdivisions of the peripheral nervous system (PNS) • Physiology • Diseases associated with PNS • Special topics (current research at Vanderbilt) Brief question- • Is there a location in our body that does not have neurons (signals being sent to move or sense)? The body’s nervous system is made up of two parts: The Peripheral Nervous System (PNS) is divided into two parts PNS: Sensory components: • Nociception • Proprioception • Mechanoreception • Thermoception Parasympathetic vs Sympathetic PNS • Includes everything outside of the brain and spinal cord • Is divided into motor and sensory subsets • Controls the “rest and relax” and “flight or fight” responses PNS: Physiology & Anatomy Dorsal Root ganglion are sensory body of the PNS Anatomy of the PNS- Dorsal Root Ganglion How the PNS sends signals to the CNS Nerve impulses carry electrical signals Myelin sheath on surrounds to the nerve to contribute to signal propagation Myelin sheath on surrounds to the nerve to contribute to signal propagation Nerve impulses carry electrical signals PNS Physiology and Anatomy • Dorsal root ganglion are the sensory bodies of the PNS • The Ventral root is responsible for motor movement • Myelin Sheath is imperative to proper nerve function Diseases associated with the PNS: Peripheral Neuropathy What is peripheral neuropathy? Peripheral Neuropathy: -Damage to peripheral nerves
    [Show full text]
  • Spinal Nerves, Ganglia, and Nerve Plexus Spinal Nerves
    Chapter 13 Spinal Nerves, Ganglia, and Nerve Plexus Spinal Nerves Posterior Spinous process of vertebra Posterior root Deep muscles of back Posterior ramus Spinal cord Transverse process of vertebra Posterior root ganglion Spinal nerve Anterior ramus Meningeal branch Communicating rami Anterior root Vertebral body Sympathetic ganglion Anterior General Anatomy of Nerves and Ganglia • Spinal cord communicates with the rest of the body by way of spinal nerves • nerve = a cordlike organ composed of numerous nerve fibers (axons) bound together by connective tissue – mixed nerves contain both afferent (sensory) and efferent (motor) fibers – composed of thousands of fibers carrying currents in opposite directions Anatomy of a Nerve Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Epineurium Perineurium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Endoneurium Nerve Rootlets fiber Posterior root Fascicle Posterior root ganglion Anterior Blood root vessels Spinal nerve (b) Copyright by R.G. Kessel and R.H. Kardon, Tissues and Organs: A Text-Atlas of Scanning Electron Microscopy, 1979, W.H. Freeman, All rights reserved Blood vessels Fascicle Epineurium Perineurium Unmyelinated nerve fibers Myelinated nerve fibers (a) Endoneurium Myelin General Anatomy of Nerves and Ganglia • nerves of peripheral nervous system are ensheathed in Schwann cells – forms neurilemma and often a myelin sheath around the axon – external to neurilemma, each fiber is surrounded by
    [Show full text]
  • Shoulder Anatomy & Clinical Exam
    MSK Ultrasound - Spine - Incheon Terminal Orthopedic Private Clinic Yong-Hyun, Yoon C,T-spine Basic Advanced • Medial branch block • C-spine transforaminal block • Facet joint block • Thoracic paravertebral block • C-spine intra-discal injection • Superficial cervical plexus block • Vagus nerve block • Greater occipital nerve block(GON) • Third occipital nerve block(TON) • Hydrodissection • Brachial plexus(1st rib level) • Suboccipital nerve • Stellate ganglion block(SGB) • C1, C2 nerve root, C2 nerve • Brachial plexus block(interscalene) • Recurrent laryngeal nerve • Serratus anterior plane • Cervical nerve root Cervical facet joint Anatomy Diagnosis Cervical facet joint injection C-arm Ultrasound Cervical medial branch Anatomy Nerve innervation • Medial branch • Same level facet joint • Inferior level facet joint • Facet joint • Dual nerve innervation Cervical medial branch C-arm Ultrasound Cervical nerve root Anatomy Diagnosis • Motor • Sensory • Dermatome, myotome, fasciatome Cervical nerve root block C-arm Ultrasound Stallete ganglion block Anatomy Injection Vagus nerve Anatomy Injection L,S-spine Basic Advanced • Medial branch block • Lumbar sympathetic block • Facet joint block • Lumbar plexus block • Superior, inferior hypogastric nerve block • Caudal block • Transverse abdominal plane(TAP) block • Sacral plexus block • Epidural block • Hydrodissection • Interlaminal • Pudendal nerve • Transforaminal injection • Genitofemoral nerve • Superior, inferior cluneal nerve • Rectus abdominal sheath • Erector spinae plane Lumbar facet
    [Show full text]
  • Neuroscience
    NEUROSCIENCE SCIENCE OF THE BRAIN AN INTRODUCTION FOR YOUNG STUDENTS British Neuroscience Association European Dana Alliance for the Brain Neuroscience: the Science of the Brain 1 The Nervous System P2 2 Neurons and the Action Potential P4 3 Chemical Messengers P7 4 Drugs and the Brain P9 5 Touch and Pain P11 6 Vision P14 Inside our heads, weighing about 1.5 kg, is an astonishing living organ consisting of 7 Movement P19 billions of tiny cells. It enables us to sense the world around us, to think and to talk. The human brain is the most complex organ of the body, and arguably the most 8 The Developing P22 complex thing on earth. This booklet is an introduction for young students. Nervous System In this booklet, we describe what we know about how the brain works and how much 9 Dyslexia P25 there still is to learn. Its study involves scientists and medical doctors from many disciplines, ranging from molecular biology through to experimental psychology, as well as the disciplines of anatomy, physiology and pharmacology. Their shared 10 Plasticity P27 interest has led to a new discipline called neuroscience - the science of the brain. 11 Learning and Memory P30 The brain described in our booklet can do a lot but not everything. It has nerve cells - its building blocks - and these are connected together in networks. These 12 Stress P35 networks are in a constant state of electrical and chemical activity. The brain we describe can see and feel. It can sense pain and its chemical tricks help control the uncomfortable effects of pain.
    [Show full text]
  • Peripheral Nervous System
    Peripheral Nervous System Nervous system consists of CNS = brain and spinal cord ~90% (90 Bil) of all neurons in body are in CNS PNS = Cranial nerves and spinal nerves ~10% (10 Bil) of all neurons in body are in PNS PNS is our link to the outside world without it CNS us useless sensory deprivation hallucinations sensory (afferent) neurons ~2-3M; 6-8x’s more sensory than motor fibers motor (efferent) neurons ~350,000 efferent fibers somatic motor neurons autonomic motor neurons these neurons are bundled into nerves difference between nerve and neuron: neuron = individual nerve cell nerve = bundle of axons outside CNS surrounded by layers of connective tissue CNS PNS Axons Tracts Nerves Cell Bodies Nuclei Ganglia Nerves consist of either sensory or motor neurons or a combination of both (=mixed nerves) mixed nerves often carry both somatic and autonomic motor fibers ganglia examples: dorsal root ganglia = cell bodies of sensory neurons autonomic chain ganglia = cell bodies, dendrites & synapses of autonomic motor neurons PNS consists of 43 pairs of nerves branching from the CNS: 12 pairs of cranial nerves 31 pairs of spinal nerves Cranial Nerves 12 pairs of cranial nerves 1 structurally originate from: cerebrum: I, II midbrain: III, IV pons: V, VI, VII,VIII (pons/medulla border) medulla: IX, X, XI, XII functionally: some are sensory only: I. Olfactory [sense of smell] II. Optic [sense of sight] VIII. Vestibulocochlear [senses of hearing and balance] -injury causes deafness some are motor only: III. Oculomotor IV. Trochlear [eye movements] VI. Abducens -injury to VI causes eye to turn inward some are mixed nerves: V.
    [Show full text]